Bradshaw said that message came during the third call from the home. "The phone went dead" in the previous two calls, he said.

"So a deputy arrives at the scene, and now this time the guy's outside ... He does have a hammer and the hedge clippers in his hand," Bradshaw said. "He's starting to close the distance between himself and the deputy, the deputy's telling him to get rid of the weapons and get on the ground.

"(He's being) non-compliant, he's still moving toward the deputy. The deputy does not know if someone has been killed inside, but he definitely knows he's not going to allow this individual to close the gap on him."

Bradshaw said family members told investigators that the teen was not taking his prescription medication, which resulted in the violent behavior.

"He's made statements to the family members and others that he's a Ninja, that he's not afraid of the police," Bradshaw said.

Parker asked the sheriff why the deputy, whose identity has not yet been released, didn't use a stun gun.

"A Taser has limited ability," Bradshaw said. "When you're dealing with this violent of a situation with somebody who has already demonstrated that they're in the process of either going to kill or trying to kill somebody, and they have the means and ability to do it, you're going to take whatever action it takes to neutralize that threat immediately," Bradshaw said. "And if that's deadly force, then that's the way it has to be."

Gen. David Petraeus pleaded guilty to federal charges Tuesday to end a probe into whether he provided classified information to his mistress when he was CIA director, according to a U.S. official briefed on the matter.